Along with the rapid advance in semiconductor technology, the integrated circuit (IC) is miniaturized, the function is diversified and the processing speed and the operation frequency are higher. To achieve these, the number of the IC input/output (I/O) pins must be increased so as to meet the requirements of multi-functional signal processing. Thus, the layout of the I/O pins is directed towards high density matrix distribution and the signal transmission are by non-contact capacitance coupling, so as to reduce the circuit size and increase the processing speed.
Non-contact probe card is used for testing in wafer-level test. However, when a non-contact probe card is used for testing a wafer, the distance between the probe card and the wafer must be properly controlled, so as to form a signal transmission path between the electrode of the probe card and the corresponding electrode of the wafer by capacitance coupling. In convention, the distance between the probe card and the wafer is controlled by a motor. However, as the distance between the probe card and the wafer is very small, it is very difficult to precisely control the distance between the probe card and the wafer by the motor and the precision control on the capacitance coupling is not easily achieved. Moreover, in convention, the probe card may collide and damage the wafer.
Thus, how to maintain the precise signal transmission in non-contact test and avoid damage to the IC on the wafer has become an imminent challenge.